docs: def feature_path_unset(self):
          """Copy features to memory and remove the association of the feature file."""
          if not self.feature_file:
              raise IOError('No feature file to unset')
  
          with open(self.feature_path) as handle:
              feats = list(GFF.parse(handle))
              if len(feats) > 1:
                  log.warning('Too many sequences in GFF')
              else:
                  tmp = feats[0].features
  
          self.feature_dir = None
          self.feature_file = None
          self.features = tmp